1. Field of the Invention
The present invention relates to a disk storage apparatus in which data is written onto a discoid recording medium (namely, a disk medium) and data is read from the recording medium by a head. More particularly, the present invention relates to an apparatus and method for controlling a write current supplied to a head in accordance with write data.
2. Description of the Related Art
A hard disk drive is known as typified by a disk storage apparatus using a disk (disk medium) as a recording medium. The write characteristic of this hard disk drive depends on the recording density (for example, the track density TPI), temperature and the like in the environment in which an apparatus is used. Thus, Jpn. Pat. Appln. KOKAI Publication No. 10-312504 discloses a technique to assure a recording density margin (TPI margin) and a temperature margin in a hard disk drive. According to this technique (which will be referred to as the prior art hereinafter), obtaining a lower limit value of a write current relative to the temperature margin and an upper limit value of the write current relative to the TPI margin can set an optimum write current without lowering characteristics of both margins. That is, the prior art is characterized in that the write current is optimized by focusing on both the TPI margin and the temperature margin.
However, when an increase in the recording density of the disk (recording medium) advances, the influence of the magnetic leakage flux from the head on an adjacent track becomes large. Therefore, it can be expected that the upper limit value of the write current relative to the TPI margin becomes lower than the lower limit value of the write current relative to the temperature margin. In this case, both margins are hard to be assured in the prior art. Further, degradation of the recording quality in a low-temperature environment occurs.